title: Chitin regulation of immune responses: an old molecule with new roles.
abstract: Chitin, the second most abundant polysaccharide in nature, is commonly found in lower organisms such as fungi, crustaceans, and insects, but not in mammals. Although the non-specific anti-viral and anti-tumor activities of chitin/chitin derivatives were described two decades ago, the immunological effects of chitin have been only recently been addressed. Recent studies demonstrated that chitin has complex and size-dependent effects on innate and adaptive immune responses including the ability to recruit and activate innate immune cells and induce cytokine and chemokine production via a variety of cell surface receptors including macrophage mannose receptor, toll-like receptor 2 (TLR-2), and Dectin-1. They also demonstrated adjuvant effects of chitin in allergen-induced type 1 or type 2 inflammation and provided insights into the important roles of chitinases and chitinase-like proteins (C/CLP) in pulmonary inflammation. The status of the field and areas of controversy are highlighted.
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Yale University School of Medicine, 300 Cedar Street (S441 TAC), P.O. Box 208057, New Haven, CT 06520-8057, United States. chungeun.lee@yale.edu
authors.forename: Chun Geun
authors.initials: CG
authors.lastname: Lee
authors.forename: Carla A
authors.initials: CA
authors.lastname: Da Silva
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Dominik
authors.initials: D
authors.lastname: Hartl
authors.forename: Jack A
authors.initials: JA
authors.lastname: Elias
mesh_terms: D000818:Animals; D002686:Chitin / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D002688:Chitinases / Q000378:metabolism; D048271:Chitosan / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D016207:Cytokines / Q000276:immunology* / Q000378:metabolism; D004847:Epithelial Cells / Q000201:enzymology / Q000276:immunology*; D006801:Humans; D008262:Macrophage Activation / Q000276:immunology; D011014:Pneumonia / Q000276:immunology; D011956:Receptors, Cell Surface / Q000276:immunology
chemical_list: D016207:Cytokines; D011956:Receptors, Cell Surface; D002686:Chitin; D048271:Chitosan; D002688:Chitinases